Voltage regulators



v Feb. 13, 1962 a. K. NAsTER 3,021,473

VOLTAGE REGuLA'roRs Filed Dec. 21. 1959 2 sheets-sheet 1 90 MOM/1.6.20

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` VOLTAGE REGULAToRs Filed nec. 21.r 1959 2 sheets-sheet 2 jga no [ypuOUTPUT JNVENToer M, YM Zorneg/s fvary over a rather widerange.

. 3,021,473 VOLTAGE REGULATORS y Bert K. Naster, 3000 Taft Road,Hollywood 4, Fla. Filed Dec. 21, 1959, Ser. No. 860,909 9 Claims. (Cl.323-45) This invention relates to new and improved voltage regulatorsadapted to supply a substantially constant output voltage, despiterather wide variations in the input voltage.

One object of the present invention is to provide new and improvedvoltage regulators of the electromagnetic or transformer type, adaptedtoV supply` a substantially 'constant voltage from an alternatingcurrent supply which is subject to wide voltage variaton.

Another object is to provide a new and improved voltage regulator of theforegoing character which is so arranged that the regulator will not beoverloaded, and `will not draw excessive current or power, if the outputterminals of the regulator are accidentally short-cir-y cuited.

A further object is to provide a new and improved voltage regulatorwhich has 'no moving parts, buty employs only rugged transformer andcapacitor units, so that the regulator will be inexpensive tomanufacture, yet will give dependable service for an indefinite time.

Furtherl objectsk and advantages of the present invention will appearfrom the following description, taken with the accompanying drawings, inwhich:

FIG. l is a schematic wiring diagram showing the i circuit arrangementof a voltage regulator to be described as one illustrative embodiment ofthe present invention. FIG. 2 is a diagrammatic view showing the layoutand connections of the transformer and capacitor units employed in theregulator. p n FIG. 3 is a plan view of the main transformer unit oftheregulator shown in FIGS. 1 and 2.

FI'G. 4`is a sectional view, taken generally along a v line 4 4 in FIG.3.

FIG. 5Y is a diagram showingthe 4'wave forms of the input and outputvoltages of the regulator.

FIGS. `6, 7 and 8. are views s'milar toFIGS. 1', 2 and 3 respectively,but showing a modified` voltage regulator. n

youtput voltage across a pair of output terminals'` 12 `and 14,V eventhough -the input voltage to the regulator may y As shown, thealternatinput voltage may be applied across apair of input terminals 16and 18. The input voltage ymaybe derived Vfrom an ordinary householdpower line, or any other source of alternating current, which may beva-t anysuitable voltage and frequency, such as ajnominal voltage of 110volts and a frequency of 60 cycles. The output voltage will not changeto any substantial .extent even 4United States Patent() ICC p L2 Thewindings P1, S1 and S2 of the rst transformer 20 are mounted on alam'nation or core 26. It is preferred to provide magnetic shunts 28 and30 between the windings. Thus, the shunt 28 is between the primary P1and the secondary S1, while the shunt 30 is between the secondaries S1and S2. Y I

` Similarly, the windings P2 and S3 of the second transformer 22 aremounted on a lamination or core 32. It is preferred to provide amagnetic shunt 34 between the wind`ngs P2 and S3. In each case, themagnetic shunts decouple ythe windings and increase -their leakagereact'ances. y V

One end of theV first kprimary winding 131 is connected to the inputterminal 16 by a lead 36. The other input terminal 18 is connected tothe output terminal 14 by lead 38. A lead 40 extends between the otheroutput terminal 12 and one end of the Secondary winding In theillustrated arrangement, all of the w'ndings P1,

'S1 and S2Qare connected in a closed series circuit or to neutralize thekpositive leakage react/ances of the windand P2y in series -across theinput terminals 16 and 18. Thu-s, the input voltage is divided betweenVthe p'rivresonant varies with the input'voltage.

the resonant condition contributes to the overall regu-y ings Pl, S1 andS2. The extent to which the circuit is This shifting in lating actionofthe regulator. n

In the case of the second transformer 22, the lwindings kP2 and S3 areconnected in series across the output 4telfn minals 12 and 14. A lead 48extends between the windings P2 and S3. Thus, the second transformer 22is also connected as an autotransformer.

The circuits ofthe transformers 20 and 22 are interconnected by meansofa lead 50 which extends between the junctfon leads 42 and 48. It willbe seen that the lead 5)y has the effect of connecting the primarywindings maries P1 and- PZ, but this etfectis modified by thepre'sthough kthe input voltage may vary over a considerable f range,such as from 8() to 140 volts, for example. yThe ytransformer units y20and 22, and a capacitor 24. The

first transformer unit comprises a primary winding P1v and ktwosecondary windings, S1 and`S2. The second transformer unit 22 has aprimaryfwinding P2 and a secondary winding S3.

- put voltage.

yence ofthe secondaries S1 and S2 and the capacitor 24 'in series withP1. -The shift-of Vthe'resonant condition in the circuit of thetransformer v20 varies the'division of thevoltage insuch a man-ner as togive art-regulated out- FIGS. V3 and 4 illustrate various details ofthefirst transformer 20. As shown, the lamination Vor core 26 comprisesranlelongated central leg 54,*on which the windings P1, S1 and S2 aremounted. The laminat'on t k26 has a generally rectangular outer member56, cornprising a pair of krelatively short end -legs l518 and 6 0,which extend between the ends of relatively long side legs 62 and ,'64.The central leg 54 extends between f end legs 58 and 60, so that theouter member 56 will provide a return path yfor the magnetic fluxgenerated by the windings P1, S1 and S2.

It is preferred to employ high reluctance, saturable joints 68 and 70between the centrall leg 54 and the end legs 58 Iand 60. Thus, the lefthand end of the central leg 54 engages the end 'leg 58 only along twosmall kdiagonal corner faces 72 and 74. The remainder of the left handend of the central leg 54 is separated frorv'the'end leg58 r lby anon-magnetic gap 76, which may be filled With' fiber 3 or other suitablematerial to minimize vibration. At the right hand end of the lamination26, the central leg 54 has a small nose portion or projection 78, whichis the only part of the central leg which actually engages the end leg60. Elsewhere, the central leg 54 is separated from the 5 end leg 60 bynon-magnetic gaps 8u and 82, which again may be iilled with fiber orsome other suitable material. The joints 68 and 76 increase the leakagereactances of the windings P1, S1 and S2. Since the magnetic iiux isconcentrated in the joint elements '72, 74 and 78, they saturate ratherreadily as the ilux increases. The saturation of the joints causes afurther increase in the leakage reactances of the windings.

In the illustrated construction, the magnetic shunts 28 and 30 take theform of projections on the side legs 62 and 64. These projections arelocated between the coils P1, S2 and S2. It will be seen that theprojections are formed integrally on the side legs 62 and 64. Theprojections extend inwardly so that they are separated from the centralleg 54 by narrow gaps 86 and 88.

The second lamination 32 is very similar in construction to the firstlamination 26. Thus, the lamination 32 comprises a central leg 90 whichextends between the ends of a rectangular outer member 92. The magneticshunts 34 take the form of projections extending inwardly toward thecentral member 90, from the outer member 92. High reluctance saturablejoints 94 and 96 are preferably provided between the central leg 90 andthe outer member 92.

The various coils may be wound with different numbers of turns in orderto provide various output voltages and regulation characteristics.However, it is thought that the following coil data, for a particularregulator which has been successfully used, will be of interest:

Winding No. ol

Turns In this regulator, the capacitor 24 had a value of 15 microfarads.

For one set of operating conditions, the voltages across the variouscoils were as follows:

These conditions existed with an output load of 224 watts and a powerinput of 300 watts.

FIG. 5 illustrates the wave forms of the input and output voltages andclearly shows the phase relation between these voltages.

In FIG. l, the wave forms of the voltages across the various coils areshown by oscillograms adjacent the coils. An additional oscillogram,adjacent the capacitor 24, shows the wave form of the voltage across thecapacitor.

The illustrated voltage regulator 10 maintains the output voltagesubstantially constant over a wide range of input voltage. This may beillustrated by the following typical regulation chart:

Input, Volts Output, Volts In this example, the variation in the outputvoltage is 75 only one and one-half volts, while the input voltagevaries over a range of sixty volts.

If the output terminals 12 and 14 are accidentally short-circuited, thehigh leakage reactance of the secondary winding S3 limits the outputcurrent so that no damage is done to the regulator. Moreover, theshortcircuit of the output throws the regulator out of resonance so thatthe regulator does not draw excessive current or power. As soon as the4short-circuit is removed, the regulator delivers normal outputvoltages. There is no need for fuses or other protective devices.

FIGS. 6 through 8 illustrate a modiiied regulator 110, which is verymuch the same as the regulator 10 except that the secondaries S1 and S2are combined into a single winding S4. The primary P1 is replaced by awinding Pla having a series of taps 112 at its right hand end so thatthe output voltage may be varied. Similarly, the secondary S3 isreplaced with a winding S3a having a series of taps 114 at its left handend.

Instead of being connected directly to the right hand end of the primarywinding Pla, lthe right hand end of the `secondary S3a is connected to aswitch member 116 which may be engaged with any of the taps 112. Theoutput lead 40 is connected to a switch member 118 which may be movedinto engagement with any of the taps 114.

As before, the windings Pla and S4 are connected in series with thecapacitor 24 to form a circuit or loop which is resonated to varyingdegrees by the capacitor, according to the current in the circuit. Theprimary windings Pla and P2 are connected in series across the inputterminals 16 and 18 as above.

As shown in FIGS. 7 and 8 the secondary S4 occupies the space formerlyoccupied by the secondaries S1 and S2, while the primary Pla replacesthe primary P1. The magnetic shunts 30 are eliminated to form a slightlymodiiied lamination 26a. Otherwise, the lamination is the same as inFIGS. 3 and 4. The lamination 32 remains the same as in FIG. 2.

The operation of the voltage regulator 110 is much the same as theoperation of the regulator 10, except that the switches 116 and 118 makeit possible to adjust the regulated output voltage over a considerablerange. It will be understood that the control switches could easily beincorporated into the regulator 10 of FIGS. 1 and 2.

The illustrated regulators provide truly remarkable voltage regulation,despite the fact that the regulators have no moving parts and are madeup of simple transformer and capacitor units. It will be apparent thatthe regulators are highly dependable, yet very inexpensive.

Various other modifications, alternative constructions Vand equivalentsmay be employed without departing from the true spirit and scope of theinvention, as exemplified in the foregoing description and dened in thefollowing claims.

I claim:

1. In a voltage regulator, the combination comprising a firsttransformer having a first primary winding and first and secondsecondary windings, a second transformer having a second primary windingand a secondary winding, a pair of input terminals for receivingalternating current, means connecting said first and second primarywindings in series across said terminals, a pair of output terminals fordelivering alternating current, means connecting said secondary primarywinding and said secondary winding of said second transformer in seriesacross said output terminals, a capacitor, and a circuit connecting saidcapacitor, said first primary winding, and irst and secod secondarywindings in a closed series loop in which said capacitor tends toneutralize the inductive reactances of said first primary winding andsaid first and second secondary windings.

2. In a voltage regulator, the combination comprising a firsttransformer having a first primary winding and Vfirst and secondsecondary windings, a second transformer sparare having a second primarywinding and a secondary 'winding, said first transformer having amagnetic core 'with a first magnetic shunt between said first primar)tvwinding and said first secondary winding, said core having a secondmagnetic shunt between first and second secondary windings, said secondtransformer hat/ing arnagnetic core with a magnetic shunt between saidsecond primary winding and said third mentioned secondary winding, apair of input terminals for receiving alternating current, meansconnecting said first and second primary windings in seriesV across saidterminals, a pair of output terminals for delivering alternatingcurrent, means connecting said second primary winding and said secondarywinding of said second transformer in series across said outputterminals, a capacitor, and a circuit connecting said capacitor, saidfirst primary winding, and first and second secondary windings in aclosed series loop in which said capacitor tends to neutralize theinductive reactances of said first primary winding and said first andsecond secondary windings. y

3. In a voltage regulator, the combination comprising a firsttransformer having a first primary winding and a first secondarywinding, a second transformer having a second primary winding and asecond secondary winding, a pair of input terminals for receivingalternating current, means connecting said first and second primarywindings in series across said input terminals, a pair of outputterminals for delivering alternating current, means connecting saidsecond primary winding and said second secondary winding in seriesacross said output terminals, a capacitor, and means connecting saidcapacitor, said first priy mary winding and said first secondary windingin series in a closed loop in which said capacitor tends to neutralizethe inductive reactances of said first primary winding andv said firstsecondary winding.

4. In a voltage regulator, the combination comprising a firsttransformer having a magnetic core, a first primary winding and a firstsecondary winding mounted on said core, said core having a magneticshunt between said first primary winding and said first secondarywinding, a second transformer having a second magnetic core, a secondprimary winding and a second secondary winding mounted on said secondcore, said second core having a magnetic shunt between said secondprimary winding and said second secondary winding, said shunts impartinghigh leakage reactances to said first and second secondary windings, apair of input terminals for receiving alternating current, meansconnecting said first and second primary windings in series across saidinput terminals, a pair of output terminals for delivering alternatingcurrent, means connecting said second primary winding and said secondsecondary winding in series across said output terminals, a capacitor,and a circuit connecting said capacitor, said first primary winding, andsaid first secondary winding in series in a closed loop in which saidcapacitor tends to neutralize the inductive reactances of said firstprimary winding and said first secondary winding.

5. In a voltage regulator, the combination comprising a firsttransformer having a first primary winding and a first secondarywinding, a second transformer having a second primary winding and asecond secondary winding, a pair of input terminals for receivingalternating current,

means connecting said first and second primary windings in series acrosssaid input terminals, one end of said second primary winding beingconnected to one end of said first primary winding, said first primarywinding having a first series of taps thereon adjacent one end thereof,a first switch for connecting one end of said second secondary windingto any of said taps, a pair of output terminals for deliveringalternating current, one of said output terminals being connected to theother end of said second primary winding, said ysecond secondary windinghaving a second series of taps thereon adjacent the other end thereof, asecond switch for connecting the other output terminal to any of saidsecond series `of taps, a capacitor,

a circuit connecting said capacitor, said first primary winding, andsaid first secondary winding in 'series in a 'a pair `of input terminalsfor receiving alternating current, means connecting rsaid first andsecond primary windings in series across said input terminals, saidsecond primary winding being connected to one end of said first primarywinding, said first primary winding having a series of taps thereonadjacent one end thereof, a switch for connecting one end of said secondsecondary winding to any of said taps, a pair of output terminals fordelivering `alternating current, one of said output terminals beingconnected to the other end of said second primary winding, meansconnecting the other output terminal to the other end of said secondarywinding, taps, a capacitor, and a circuit connecting said capacitor,said first primary winding, and said first secondary winding in seriesin a closed loop.

7. In a voltage regulator, the combination comprising a firsttransformer having a first primary winding and a first secondarywinding, a second transformer having a second primary winding and asecond secondary winding, a pair of input terminals for receivingalternating current, means connecting said first and second primarywindings in series across said input terminals, one end of said secondprimary winding being connected to one end of said first primarywinding, one end of said second secondary winding being connected tosaid one end of said second primary winding, a pair of output terminalsfor delivering alternating current, one of said output terminals beingconnected to the other end of said second primary winding, said secondsecondary winding having ya series of taps thereon adjacent the otherend thereof, a second switch for connecting the other output terminalsto any of said series of taps, a capacitor, and a circuit connectingsaid capacitor, said first primary winding, and said first secondarywinding in series in a closed loop.

8. In a voltage regulator, the combination comprising a firsttransformer having a magnetic core, a first primary winding and a firstsecondary winding mounted on said core, said core having a magneticshunt between said first primary winding and said first secondarywinding, said shunt imparting high leakage reactances to said yfirstsecondary winding, a second transformer having a kmeans connecting saidsecond primary winding and said second secondary winding in seriesacross said outrput terminals, a capacitor, and a circuit connectingsaid capacitor, said first primary winding, and said first secondarywinding in series in ay closed loop in which said f capacitor tends toneutralize the inductive reactances of said first primary winding andsaid first secondary winding.

9. in a voltage regulator, the combination comprising a firsttransformer having a magnetic core, a first primary winding and firstand second secondary windings mounted on said core, said core having amagnetic shunt between said first primary winding and said firstsecondary winding, a second transformer having a second magnetic core, asecond primary winding and an additional secondary winding mounted onsaidk second core, said second core having a magnetic shunt between saidsecond primary winding and said additional secondary winding, saidshunts imparting high leakage reactances to said secondary windings, apair of input ter 7 mina'ls for receiving alternating current, meansconnecting said first and second primary windings in series across saidinput terminals, a pair of output terminals for delivering alternatingcurrent, means connecting said second primary winding and saidadditional secondary winding in series across said output terminals, acapacitor, and a circuit connecting said capacitor, said rst primarywinding, and said iirst and second secondary windings in series in aclosed loop in which said capacitor tends to neutralize the inductivereactances of said first primary winding and said first and secondsecondary windings.

References Cited in the le of this patent UNITED STATES PATENTS UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,021,473February 13w 1962 Bert K Naster It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

Column 4, line 65, for "secondary" read second Signed and sealed this5th day of June 19620 (SEAL) Attest:

ERNEST w. swIDEH DAVID L LADD Attesting Officer Commissioner of Patents

